A display apparatus may be classified into a cathode ray tube (CRT), a liquid crystal display (LCD) apparatus, a plasma display panel (PDP), an organic electro luminescent display (OELD) apparatus, etc. A monitor for a computer may include the LCD apparatus. The LCD apparatus has low luminance, narrow viewing angle, etc. The CRT has heavy weight, large volume, etc.
The OELD apparatus has various characteristics, for example, such as low cost, high luminance, thin thickness, light weight, etc.
The OELD apparatus generates a light using an electro-luminescence of an organic material or polymers. When an electric energy is applied to the organic material or the polymers, the light is generated through the electro-luminescence. Therefore, a backlight may be omitted so that the OELD apparatus has thinner thickness and lower cost than the LCD apparatus. In addition, the OELD apparatus has wider viewing angle and higher luminance than the LCD apparatus.
FIG. 1 is a circuit diagram showing a pixel of a conventional organic electro luminescent panel.
Referring to FIG. 1, an organic electro luminescent driving element of the conventional organic electro luminescent panel includes a switching transistor (QS), a storage capacitor (Cst), a driving transistor (QD) and an organic electro luminescent element. Current supply lines (VDD lines) are formed with data lines in a direction that is substantially in parallel with the data line. A pixel is electrically connected to each of the current supply lines (VDD lines). The number of the pixels is equal to that of scan lines.
The organic electro luminescent display (OELD) apparatus has lower luminance than the cathode ray tube (CRT). An organic electro luminescent display (OELD) apparatus of a passive type has lower luminance than an organic electro luminescent display (OELD) apparatus of an active type. The organic electro luminescent display (OELD) apparatus of a passive type generates the light when a voltage is applied to one of the scan lines. An active layer of a light emitting cell generates the light in proportion to an amount of a current that is applied to the active layer.
A cross-talk may be formed in a direction that is substantially in parallel with the current supply lines (VDD lines) while the organic electro luminescent panel is operated.
FIG. 2 is a plan view showing a cross-talk of a conventional organic electro luminescent panel.
Referring to FIG. 2, when a voltage drop of each of the current supply lines (VDD lines) corresponding to a column A where a white block is not displayed is small and a voltage drop of each of the current supply lines (VDD lines) corresponding to a column B where the white is displayed is large, pixels in the column B, which receive a current from each of the current supply lines (VDD lines) of the column B display a dark gray color.
Therefore, pixels disposed adjacent to an upper portion of the white block and a lower portion of the white block display the dark gray color that is darker than that of pixels spaced apart from the white block, thereby forming the cross-talk. In addition, the voltage drop of each of the current supply lines (VDD lines) increases in proportion to a size of the white block.
Furthermore, a luminance of the pixels disposed adjacent to the upper and lower portions of the white block decreases in proportion to the size of the white block, therefore forming the cross-talk.
The luminance of the pixels decreases in inverse proportion to a light emitting area, and a change of the luminance in a longitudinal direction is greater than that in the horizontal direction.